When someone (usually speaking for or about a religion) claims that their beliefs are the one and only truth. While they may not directly impress their beliefs on others, they speak of their beliefs as if it is not possible that the literally thousands of other belief structures out there could be a correct one.

"The only truth in this world is that Christ is the one true savior"

"Hey man, no one knows which religion is right or wrong in the end, not even you, so quit truth hoarding"